Scoping of material response under DEMO neutron irradiation: comparison with fission and influence of nuclear library selection

TL;DR

This study comprehensively evaluates material activation, transmutation, and damage under DEMO fusion neutron irradiation, comparing with fission conditions and nuclear data libraries to inform future fusion reactor material assessments.

Contribution

It provides a detailed database of material responses under fusion neutron spectra, highlighting differences from fission and the impact of nuclear data library choices.

Findings

Fusion neutron irradiation leads to distinct activation and damage profiles compared to fission.

Nuclear data libraries show significant variations affecting response predictions.

Fission data cannot reliably predict fusion material behavior.

Abstract

Predictions of material activation inventories will be a key input to virtually all aspects of the operation, safety and environmental assessment of future fusion nuclear plants. Additionally, the neutron-induced transmutation (change) of material composition (inventory) with time, and the creation and evolution of configurational damage from atomic displacements, require precise quantification because they can lead to significant changes in material properties, and thus influence reactor-component lifetime. A comprehensive scoping study has been performed to quantify the activation, transmutation (depletion and build-up) and immediate damage response under neutron irradiation for all naturally occurring elements from hydrogen to bismuth. The resulting database provides a global picture of the response of a material, covering the majority of nuclear technological space, but focussing specifically on typical conditions expected for a demonstration fusion power plant (DEMO). Results from fusion are compared against typical fission conditions for selected fusion relevant materials, demonstrating that the latter cannot be relied upon to give accurate scalable experimental predictions of material response in a future fusion reactor. Results from different nuclear data libraries are also compared, highlighting the variations and deficiencies.